Medical devices including vascular access kits and methods of using the kit are disclosed. In some embodiments, a conduit is measured using an outside diameter measurement apparatus to determine if the conduit is compatible with a connector such that there is a continual lumen between the conduit and the connector. In some embodiments, various outside diameter measurement devices and the methods of their use are disclosed. In some embodiments, the methods of connecting a conduit, and in some embodiments a strain relief structure, to a connector are described.